The present invention relates generally to a channel access module for use in a patch unit assembly, and more particularly, to a channel module having an improved monitor plug for directly monitoring certain leads of a data transmission circuit and having an improved switching means between the respective leads of the equipment and modem.
Several types of patch unit assemblies, and in particular, digital patch unit assemblies presently exist in the prior art. Some of these assemblies consist of a unit frame or rack in which a plurality of patching modules are disposed in side-by-side relationship. Each of these patch modules is individually removable without affecting operation of the others and each includes an access to the leads on the equipment or computer side of a data transmission circuit and an access to the leads on the modem side of a data transmission circuit. These prior art patch modules also include a switching means positioned between the equipment and modem for either electrically connecting their respective leads or disconnecting them so that access can be gained to the individual leads. Most of these prior art devices include suitable patch cords designed for use wih the unit in order to patch the leads from a designated piece of equipment to a desired modem, or vice versa. This is accomplished by inserting one plug of the patch cord into the desired equipment access opening and the other plug of the patch cord in the desired modem access opening. Insertion of such plugs into the respective access openings opens the normal data transmission circuit within the module and permits cross patching of the various equipment and modem leads.
Means are also provided in these prior art patch modules for monitoring the data transmission circuit between the equipment and modem. Access for monitoring is normally provided by an appropriate access opening in the front of the module panel. A monitor access plug similar to the patch plugs referred to is utilized to gain access to the data transmission leads and for electrically connecting such leads via a monitor plug cord to a separate monitor power module physically separated from the module being monitored. Normally, this monitoring power module is positioned on one end of an array of access modules and includes a plurality of LED indicator lamps and pin-jack access points for the break-out or testing of certain of the data transmission leads. A typical patch unit assembly of the type described above is disclosed in U.S. Pat. No. 4,037,186.
The principal drawback of the above described prior art devices is that they are not capable of monitoring more than one of the patch modules at any one time. A typical path unit assembly of the prior art contains only a single power and monitoring unit positioned to provide a monitoring function for an array (usually about 10 to 20) of individual modular units. Accordingly, only one of the modular units can be monitored at any one time. A further drawback is that the monitor power unit positioned within the patch unit assembly takes up and reduces the space which might otherwise be utilized by functioning modular access modules.
Therefore, a need exists in the art for a patch module with a monitor feature capable of monitoring more than one module simultaneously while at the same time providing increased space for such modules.